1. Field of the Invention
The present invention relates generally to a two part flywheel having a torsional vibration damper, in particular for installation in the drive train of a motor vehicle.
2. Background Information
To damp torsional vibrations in the drive train of a motor vehicle, German Utility Model 94 14 314 describes a flywheel which has two inertial masses. A first inertial mass system is fastened to the crankshaft of an internal combustion engine and a second inertial mass system is mounted so that it can rotate on the first inertial mass system and simultaneously form a friction surface of a friction clutch. The two inertial mass systems are connected to one another with rotational elasticity by means of a spring system. There is also a third inertial mass system which can rotate around the common axis of rotation of the two inertial mass systems. The third inertial mass system is in the form of a planet carrier or a ring gear of a planetary gear train. The sun wheel is non-detachably connected to the first inertial mass system and is engaged in the conventional manner with at least one planet wheel. The planet wheel can rotate on the common axis of rotation axially parallel to the planet carrier. To the extent that the planet carrier is used as the third inertial mass, the planet wheels are engaged with the ring gear which is then non-detachably fastened to the second inertial mass system. In embodiments in which the ring gear forms the third inertial mass, the planet carrier of the planetary gear train is a component of the second inertial mass system. Known flywheels which have a plurality of inertial masses are comparatively complex and require a relatively large amount of space in the axial and/or radial direction for the installation of the components of the planetary gear train. Additionally, the mounting of the third inertial mass is difficult because the central area of the system of inertial masses is required for the installation of a number of components of the torsional vibration damper, in particular for the installation of the bearing which is used to mount the second inertial mass system on the first inertial mass system, as well as for the installation of friction devices, if such friction devices are present. The rotational mounting of components such as a ring gear, for example, on a relatively large diameter is also problematic.
An additional flywheel which has multiple inertial masses is described in German Patent No. 195 17 605. On this flywheel, a first inertial mass system is rotationally elastically coupled by means of a spring system with a second inertial mass system. The second inertial mass system is mounted so that it can rotate relative to the first inertial mass system. The first inertial mass system also forms the ring gear of a planetary gear train which is coaxial to the axis of rotation of the crankshaft. The sun wheel of the planetary gear train is rotationally mounted on the crankshaft and is driven by means of the planet wheels which are engaged with the sun wheel and the ring gear. The planet wheels are also mounted on a planet carrier which is non-detachably connected to the engine and rotates in the direction opposite to the direction of rotation of the crankshaft. A third inertial mass which is non-detachably connected to the sun wheel ensures compensation for irregularities in the rotation of the crankshaft.